JP2019108296A - Organic electroluminescent element compound - Google Patents

Abstract

To provide an organic EL element compound that can improve an element life and current efficiency of an organic EL element produced by a solution coating method.SOLUTION: An organic EL element compound is represented by the following formula (1).SELECTED DRAWING: None

Description

  The present invention relates to a compound for an organic electroluminescent device, a liquid composition, a thin film and an organic electroluminescent device (organic EL device).

  2. Description of the Related Art In recent years, development of display devices and lighting devices using organic light-emitting diodes (OLEDs), which are self-luminous light-emitting elements, has been actively conducted.

  In general, the organic EL element has a structure in which, for example, an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode are sequentially stacked. In the organic EL element, excitons are generated by recombination of holes and electrons injected from the anode and the cathode in the light emitting layer. In addition, the generated excitons emit light by transitioning to the ground state.

  Such organic EL elements are required to improve current efficiency and element life. Therefore, research on materials for organic EL devices used in each layer is advanced, and various materials are proposed. For example, Patent Document 1 describes that a triazine compound having a specific bending structure is used as a host material of a light emitting layer.

  On the other hand, in the organic EL element, in order to manufacture a large-area element at low cost (cost), it has been studied to use a solution coating method instead of the vacuum evaporation method. In the solution coating method, the utilization efficiency of the material for an organic EL element is high compared to the vacuum evaporation method, a large area can be easily formed, and it is not necessary to use an expensive vacuum device. For this reason, the solution coating method is being developed as an efficient method of manufacturing an organic EL element, and development of a material suitable for the solution coating method is also in progress. For example, Patent Document 2 discloses a material that has been improved so that the compounds described in Patent Document 1 can be solubilized and applied to a solution coating method.

U.S. Patent Application Publication No. 2015/228908 US Patent Application Publication No. 2017/174705

  However, it is required to improve the device life and current efficiency of the organic EL device manufactured by the solution coating method.

  One aspect of this invention aims at providing the compound for organic EL elements which can improve the element life and current efficiency of the organic EL element manufactured by the solution apply | coating method in view of the said problem.

  In order to solve the said subject, according to 1 aspect of this invention, the compound for organic electroluminescent elements represented by following formula (1) is provided.

（式（１）中、Ａは、下記式（２）で表される化合物から１個の水素原子を除いた基であり、ｎは、２〜８の整数であり、Ｌは、ｎ価の連結基であり、単結合であってもよい。）

(In the formula (1), A is a group obtained by removing one hydrogen atom from the compound represented by the following formula (2), n is an integer of 2 to 8, and L is an n-valent A linking group, which may be a single bond)

（式（２）中、Ａ_１〜Ａ_４は、それぞれ独立に、置換若しくは無置換のアリール基、置換若しくは無置換のヘテロアリール基又は置換若しくは無置換のアルキル基であり、Ａ_１及びＡ_２は、互いに結合して環を形成してもよく、Ｘは、−Ｎ＝又は−ＣＲ＝（ただし、Ｒは、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、複数のＸは、同一であっても、異なっていてもよく、Ａ_３及びＡ_４のうち、少なくとも１つは、置換若しくは無置換のアジン環基若しくは下記式（３）で表される基を含む、アリール基又は置換若しくは無置換のアジン環基若しくは下記式（３）で表される基を含む、ヘテロアリール基であり、Ａ_３及びＡ_４が置換される位置は非対称である。）

(In formula (2), A _{1 to} A ₄ each independently represent a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group, and A ₁ and A ₂ And X may be bonded to each other to form a ring, and X may be —N = or —CR = (wherein R is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted A plurality of X may be the same or different, and at least one of A ₃ and A ₄ is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group); An aryl group, a substituted or unsubstituted azine ring group, or a heteroaryl group including a group represented by the following formula (3), which contains a non-substituted azine ring group or a group represented by the following formula (3) , _{A 3} and A Position is asymmetric but to be replaced.)

（式（３）中、Ｘは、−Ｎ＝又は−ＣＲ_１＝（ただし、Ｒ_１は、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、複数のＸは、同一であってもよいし、異なっていてもよく、Ｙは、それぞれ独立に、−Ｏ−、−Ｓ−、−ＮＲ_２−（ただし、Ｒ_２は、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）又は−ＣＲ_３Ｒ_４−（ただし、Ｒ_３及びＲ_４は、それぞれ独立に、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、Ｚは、置換若しくは無置換の環形成炭素数６〜３０の芳香族炭化水素環又は置換若しくは無置換の環形成原子数５〜３０の芳香族複素環であり、Ｒ_５は、置換若しくは無置換のアリール基、置換若しくは無置換のヘテロアリール基又は置換若しくは無置換のアルキル基である。）

(In the formula (3), X represents -N = or -CR ₁ = (wherein R ₁ represents a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or substituted group A plurality of X's may be identical or different, and each Y independently represents -O-, -S- or -NR ₂ - (. However, R ₂ is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group), or -CR ₃ R ₄ - (However, R ₃ and R ₄ are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group). Yes Z An aromatic heterocyclic ring substituted or unsubstituted aromatic ring formed C6-30 hydrocarbon ring or a substituted or unsubstituted ring atoms 5 to 30, R ₅ is a substituted or unsubstituted aryl A group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group)

  According to one aspect of the present invention, it is possible to provide a compound for an organic EL device capable of improving the device life and current efficiency of the organic EL device manufactured by a solution coating method.

It is a schematic diagram which shows an example of the organic EL element which concerns on this embodiment.

  Below, the form for implementing this invention is demonstrated.

<Compound>
First, a compound for an organic EL device according to the present embodiment will be described. The compound for organic EL elements which concerns on this embodiment is a compound represented by following formula (1).

（式（１）中、Ａは、下記式（２）で表される化合物から１個の水素原子を除いた基であり、ｎは、２〜８の整数であり、Ｌは、ｎ価の連結基であり、単結合であってもよい。）

(In the formula (1), A is a group obtained by removing one hydrogen atom from the compound represented by the following formula (2), n is an integer of 2 to 8, and L is an n-valent A linking group, which may be a single bond)

（式（２）中、Ａ_１〜Ａ_４は、それぞれ独立に、置換若しくは無置換のアリール基、置換若しくは無置換のヘテロアリール基又は置換若しくは無置換のアルキル基であり、Ａ_１及びＡ_２は、互いに結合して環を形成してもよく、Ｘは、−Ｎ＝又は−ＣＲ＝（ただし、Ｒは、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、複数のＸは、同一であっても、異なっていてもよく、Ａ_３及びＡ_４のうち、少なくとも１つは、置換若しくは無置換のアジン環基若しくは下記式（３）で表される基を含む、アリール基又は置換若しくは無置換のアジン環基若しくは下記式（３）で表される基を含む、ヘテロアリール基であり、Ａ_３及びＡ_４が置換される位置は非対称である。）

(In formula (2), A _{1 to} A ₄ each independently represent a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group, and A ₁ and A ₂ And X may be bonded to each other to form a ring, and X may be —N = or —CR = (wherein R is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted A plurality of X may be the same or different, and at least one of A ₃ and A ₄ is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group); An aryl group, a substituted or unsubstituted azine ring group, or a heteroaryl group including a group represented by the following formula (3), which contains a non-substituted azine ring group or a group represented by the following formula (3) , _{A 3} and A Position is asymmetric but to be replaced.)

（式（３）中、Ｘは、−Ｎ＝又は−ＣＲ_１＝（ただし、Ｒ_１は、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、複数のＸは、同一であってもよいし、異なっていてもよく、Ｙは、それぞれ独立に、−Ｏ−、−Ｓ−、−ＮＲ_２−（ただし、Ｒ_２は、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）又は−ＣＲ_３Ｒ_４−（ただし、Ｒ_３及びＲ_４は、それぞれ独立に、水素原子、重水素原子、置換若しくは無置換のアルキル基、置換若しくは無置換のアリール基又は置換若しくは無置換のヘテロアリール基である。）であり、Ｚは、置換若しくは無置換の環形成炭素数６〜３０の芳香族炭化水素環又は置換若しくは無置換の環形成原子数５〜３０の芳香族複素環であり、Ｒ_５は、置換若しくは無置換のアリール基、置換若しくは無置換のヘテロアリール基又は置換若しくは無置換のアルキル基である。）
ただし、上記式（２）で表される化合物は、１個以上の水素原子を有する。

(In the formula (3), X represents -N = or -CR ₁ = (wherein R ₁ represents a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or substituted group A plurality of X's may be identical or different, and each Y independently represents -O-, -S- or -NR ₂ - (. However, R ₂ is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group), or -CR ₃ R ₄ - (However, R ₃ and R ₄ are each independently a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group). Yes Z An aromatic heterocyclic ring substituted or unsubstituted aromatic ring formed C6-30 hydrocarbon ring or a substituted or unsubstituted ring atoms 5 to 30, R ₅ is a substituted or unsubstituted aryl A group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group)
However, the compound represented by the said Formula (2) has one or more hydrogen atoms.

  Further, the compound represented by the above formula (1) is excellent in the electron transporting ability and the electron injecting ability since the 9 position of the carbazole ring is substituted by a fluorene ring as represented by the above formula (2) ing. Therefore, it is possible to use suitably as a component of an organic EL element.

The aryl group in A _{1 to} A ₄ is not particularly limited. For example, monocyclic aryl group such as phenyl group, biphenyl group, terphenyl group, quaterphenyl Group, non-fused polycyclic aryl group such as quinquephenyl group, sexiphenyl group, fluoroanthenyl group, triphenylenyl group, etc., naphtyl group, anthryl group, Phenanthryl group, fluorenyl group, indenyl group, pyrenyl group, aceto Futeniru (Acetonaphtenyl) group, bisphenyl fluorenyl (bis-phenylfluorenyl) group, and a 9 (9-fluorenyl) fluorenyl (9 (9-fluorenyl) fluorenyl) fused polycyclic aryl group such group. The number of ring-forming carbon atoms of the aryl group is not particularly limited, but is preferably 6 to 50, and more preferably 6 to 40.

The heteroaryl group in A _{1 to} A ₄ is not particularly limited, and examples thereof include pyrrolyl group, imidazolyl group, imidazolyl group, pyrazolyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group. (Oxadazolyl) group, thiazolyl group, furanyl group, pyranyl group, pyrenyl group, pyridyl group, pyridyl group, pyrazyl group, pyrimidinyl group, pyridazinyl group (pyridazinyl group) Group, triazinyl group, quinolyl group, isoquinolyl (is monocyclic heteroaryl group such as quinolyl group, benzo (pyridyl) furanyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, carbolinyl group Group, phenanthridinyl group, acridinyl group, perimidinyl group, phenanthrolinyl group, benzoxazolyl group, benzothiazolyl group, quinoxalyl group Group, benzimidazolyl (benzimidazole ) Group, pyrazolyl (pyrazolyl) group, dibenzofuranyl (Dibenzofuranyl) group, dibenzothienyl (Dibenzothienyl) group, and a polycyclic heteroaryl group of azine ring group to be described later. The number of ring carbon atoms of the heteroaryl group is not particularly limited, but is preferably 5 to 50, and more preferably 5 to 30.

The alkyl group in A _{1 to} A ₄ can be a linear, branched or cyclic alkyl group. The linear, branched or cyclic alkyl group is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group and an octyl group. , Linear alkyl group such as decyl (decyl) group, pentadecyl (pentadecyl) group, branched alkyl group such as t-butyl group, cyclobutyl group, cyclopentyl (cyclopentyl) group, cyclohexyl group, Mention may be made of cycloalkyl groups such as cycloheptyl groups. The number of carbon atoms in the linear or branched alkyl group is not particularly limited, but is preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 5, and still more preferably 1 It is ~ 3. The number of carbon atoms in the cyclic alkyl group is not particularly limited, but is preferably 3 to 20, more preferably 3 to 12, still more preferably 3 to 10, and still more preferably 4 to 7. is there.

  Also, the substituent that can be substituted to the above-mentioned aryl group, heteroaryl group and alkyl group is not particularly limited, but, for example, a cyano (cyano) group, a silyl (silyl) group, and 1 to 10 carbon atoms Mono (mono), di (di) or tri-alkylsilyl group, linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, alkyl group having 1 to 4 carbon atoms 10 linear or branched alkoxy groups, aryl groups having 6 to 15 ring carbon atoms, aryloxy groups having 6 to 15 ring carbon atoms, 6 to 6 ring carbon atoms 15 arylcarbonyl (arylcarbonyl) groups, heterocyclyl having 3 to 32 ring carbon atoms Groups, mono (mono-) or di (di-) alkylamino groups having 1 to 10 carbon atoms, and mono (mono-) or di (di-) arylamino groups having 6 to 15 ring carbon atoms. Can.

  In addition, unless otherwise indicated, "substituted" means being substituted by the above-mentioned substituent.

A ₁ and A ₂ are preferably substituted or unsubstituted aryl groups, more preferably substituted or unsubstituted monocyclic aromatic hydrocarbon groups or non-fused polycyclic aromatic hydrocarbon groups More preferably, it is a substituted or unsubstituted phenyl group, biphenyl group, terphenyl group or quaterphenyl group.

In addition, as described above, at least one of A ₃ and A ₄ is an aryl group including the above-mentioned substituted or unsubstituted azine ring group or a group represented by the above formula (3), or the above-mentioned substituted or unsubstituted group It is a heteroaryl group containing a substituted azine ring group or a group represented by the above formula (3). Here, when A ₃ and A ₄ are not these groups, A ₃ and A ₄ are preferably substituted or unsubstituted aryl groups, and substituted or unsubstituted monocyclic aromatic hydrocarbon groups or The non-fused polycyclic aromatic hydrocarbon group is more preferably a substituted or unsubstituted phenyl group, a biphenyl group, a terphenyl group or a quaterphenyl group.

Also, as described above, R ₅ is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group.

Examples of the aryl group, heteroaryl group and alkyl group for R ₅ include the various aryl groups, heteroaryl groups and alkyl groups described above.

The aryl group, heteroaryl group and alkyl group in R ₅ may be substituted by a plurality of substituents. In this case, a plurality of substituents may be bonded to each other to form a ring.

Further, the aryl group in R _5, heteroaryl groups, alkyl groups, polyvalent substituent is an aryl group, a heteroaryl group, may be substituted at multiple sites alkyl group. In this case, the polyvalent substituent, an aryl group, a heteroaryl group, as a linking group between the alkyl group, an alkylene group _{(-C a H} b -), oxy group (-O-), a thio group (- S-) etc. may be inserted. For example, in R ₅ , when a diarylamino group having a second and third aryl group (for example, a phenyl group) is bonded to a first aryl group (for example, a phenyl group), the second and third groups may be The aryl group may be bonded to the first aryl group. In addition, a linking group (for example, an oxy group) may be inserted between the second and third aryl groups and the first aryl group.

R ₅ is preferably a substituted or unsubstituted six-membered ring group or a six-membered ring assembly group.

Here, the substituted or unsubstituted aryl group for R _{5 and} the substituted or unsubstituted heteroaryl group are exemplified below. However, the substituted or unsubstituted aryl group in R _{5 and} the substituted or unsubstituted heteroaryl group are not limited to the groups exemplified below.

上述した中でも、Ｒ_５としては、Ｒ−１４又はＲ−１５で表される基が好ましい。

Among the above, as R ₅ , a group represented by R-14 or R-15 is preferable.

In the above formula (1), L is an n-valent linking group as described above, but is preferably a divalent linking group, and is preferably a substituted or unsubstituted alkylene group or a substituted or unsubstituted arylene group , -O-, -S-, -NR _6- (wherein R ₆ is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl Or a single bond is more preferred.

  As an alkylene group in L, C1-C20, Preferably it is 1-10, More preferably, the linear or branched alkylene group of 1-3 can be mentioned. A methylene group, ethylene group, n-propylene group, n-butylene group etc. can be mentioned as a specific example of an alkylene group.

  As an arylene group in L, a phenylene group, biphenylene group, terphenylene group, fluorenediyl group etc. can be mentioned, for example.

Examples of the aryl group, heteroaryl group and alkyl group for R ₆ include the various aryl groups, heteroaryl groups and alkyl groups described above.

  In particular, L is preferably a substituted or unsubstituted arylene group or a single bond, and more preferably a phenylene group or a single bond.

  In formula (2), X is -N = or -CR = as described above. However, among a plurality of X, at least one X is preferably -N =, one to three X are preferably -N =, and one or two X are -N = Is more preferred.

In the formula (3), X is as described above, is -N = or -CR ₁ =. However, among a plurality of X, at least one X is preferably -N =, one to three X are preferably -N =, and one or two X are -N = Is more preferred.

Examples of the aryl group, heteroaryl group and alkyl group for R and R ₁ include the various aryl groups, heteroaryl groups and alkyl groups described above.

Y is -O-, -S-, -NR ₂ -or -CR ₃ R _4- as described above. Among these, Y is preferably -O-, -S- or -NR _2- , and more preferably -S-.

Examples of the aryl group, heteroaryl group and alkyl group in R ₂ , R ₃ and R ₄ include various aryl groups, heteroaryl groups and alkyl groups described above.

  In Formula (3), as described above, Z is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 ring carbon atoms or a substituted or unsubstituted aromatic heterocycle having 5 to 30 ring atoms. It is.

  Examples of the aromatic hydrocarbon ring and the aromatic heterocyclic ring in Z include aromatic hydrocarbon rings and aromatic heterocyclic rings corresponding to the various aryl groups and heteroaryl groups described above.

  In addition, Z is preferably a six-membered ring in view of its chemical stability.

Here, specific examples of the compound in which a hydrogen atom is added to the azine ring group in A ₃ and A ₄ or the group represented by the formula (3) are exemplified below. However, the azine ring group or the group represented by the formula (3) is not limited to a group in which one hydrogen atom has been removed from the compounds exemplified below.

上述した中でも、Ａ_３及びＡ_４としては、２−２又は２−３で表される化合物から１個の水素原子を除いたアジン環基が好ましい。

Among the above, as A ₃ and A ₄ , an azine ring group in which one hydrogen atom is removed from the compound represented by 2-2 or 2-3 is preferable.

  The compound represented by the above formula (1) is preferably such that A-H or n is an integer of 2 to 4, more preferably A-H or n is 2, and further preferably A-H. By this, it is possible to synthesize in a relatively short process, it is possible to purify with high purity, and the solubility to the ester organic solvent becomes high.

  Here, specific examples of the compound represented by the formula (1) are exemplified below. However, the compound represented by Formula (1) is not limited to the compound illustrated below.

なお、式（１）で表される化合物は、公知の有機合成反応を用いて合成することが可能である。式（１）で表される化合物の具体的な合成方法は、後述する実施例を参照した当業者であれば、容易に理解することが可能である。

In addition, it is possible to synthesize | combine the compound represented by Formula (1) using well-known organic synthesis reaction. The specific synthesis method of the compound represented by the formula (1) can be easily understood by those skilled in the art with reference to the examples described later.

  Here, since the compound represented by Formula (1) is provided with the group represented by Formula (3) as mentioned above, it is excellent in the solubility with respect to an ester type organic solvent. In addition, as described above, the compound represented by the formula (1) has a relatively high glass transition temperature (Tg), and therefore, after film formation, when the solvent is removed, the compound is degraded or deformed by heat. It is hard to do. Therefore, the compound represented by Formula (1) can be suitably applied to a solution coating method. Further, the organic layer formed by the solution coating method using the compound represented by the formula (1) has less unevenness in thickness and becomes uniform. Furthermore, the organic layer has a smooth surface. Therefore, the organic EL device manufactured by the solution coating method using the compound represented by the formula (1) has high current efficiency and long device life because the application unevenness of the drive voltage and the light emission unevenness are small.

  The compound represented by Formula (1) has a comparatively high glass transition temperature, and is excellent in thermal stability. Therefore, the organic EL element containing the compound represented by Formula (1) is comparatively stable with respect to driving heat. Then, as a result of suppressing deterioration and deformation of the organic EL element due to driving heat, the element life of the organic EL element containing the compound represented by the formula (1) can be extended as compared with the conventional organic EL element it can.

  At this time, the compound represented by the formula (1) preferably has a glass transition temperature of 120 ° C. or more, more preferably 125 ° C. or more, and still more preferably 140 ° C. or more. The glass transition temperature can be measured, for example, by the method defined in JIS K 7121 or the corresponding ISO 3146. In the examples described below, the glass transition temperature is measured by differential scanning calorimetry.

  As described above, the solution coating method is expected as a more efficient method of manufacturing an organic EL element. However, the organic EL element material applicable to the solution coating method is required to have high solubility in a solvent and high stability of a thin film containing the organic EL element material after application.

  From the above, when the compound represented by the formula (1) is used, it is possible to improve the current efficiency and the device life of the organic EL device. Moreover, when the compound represented by Formula (1) is applied to a solution coating method, there is no unevenness of thickness and a uniform organic layer can be formed.

  The molecular weight of the compound represented by formula (1) is preferably 850 to 3,000, and more preferably 850 to 2,500. When the molecular weight of the compound represented by the formula (1) is 850 or more, the heat resistance of the compound represented by the formula (1) is improved, and when it is 3000 or less, the solubility in the ester organic solvent is improves.

  The solubility of the compound represented by the formula (1) in methyl benzoate at 25 ° C. is preferably 0.5% by mass or more, and more preferably 1% by mass or more.

  Furthermore, the compound represented by Formula (1) can be used as a host material or a charge transport material.

  Further, the mass ratio of the compound represented by the formula (1) to the compound having a hole transporting ability at the time of producing the organic EL element is not particularly limited, but is, for example, 100: 0 to 1:99. Preferably 95: 5 to 5:95.

<Liquid composition>
The liquid composition which concerns on this embodiment is used for manufacture of an organic electroluminescent element, for example, it is used for formation of the each layer of an organic electroluminescent element by the solution coating method.

  The liquid composition according to the present embodiment contains a compound represented by Formula (1) and a solvent.

  Here, when the liquid composition according to the present embodiment is used for forming a light emitting layer, the liquid composition according to the present embodiment includes a light emitting material described later.

  Although it does not specifically limit as a solvent, It is preferable that it is possible to dissolve the compound represented by Formula (1). That is, the liquid composition according to the present embodiment is preferably a solution composition.

  The solvent is not particularly limited, and, for example, toluene (xylene), xylene (xylene), ethylbenzene (ethylbenzene), diethylbenzene (diethylbenzene), methycylene (mesitylene), propylbenzene (propylbenzene), cyclohexylbenzene (cyclohexylbenzene), dimethoxybenzene (Dimethoxybenzene), anisole (anisole), ethoxytoluene (ethoxytoluene), phenoxytoluene (phenoxytoluene), isopropylbiphenyl (isopropylbiphenyl), dimethylanisole (dimethylanisole), phenyl acetate (phenylacetate) acetate, phenyl propionic acid, methyl benzoate, ethyl benzoate and the like.

  The concentration of the compound represented by Formula (1) in the liquid composition is not particularly limited, and can be appropriately adjusted depending on the use.

<Thin film>
The thin film according to the present embodiment contains the compound represented by the formula (1).

<Organic EL element>
Next, the organic EL element according to the present embodiment will be described.

  An example of the organic EL element which concerns on FIG. 1 at this embodiment is shown.

  The organic EL device 100 includes a first electrode 120, a hole injection layer 130, a hole transport layer 140, a light emitting layer 150, an electron transport layer 160, an electron injection layer 170, and a second electrode 120 on a substrate 110. The electrodes 180 are stacked in order.

  Here, the compound represented by Formula (1) is included in the organic layer provided between the first electrode 120 and the second electrode 180 provided to face the first electrode 120. Specifically, the compound represented by Formula (1) is preferably contained in the light emitting layer 150 as a host material.

  Moreover, although the organic layer containing the compound represented by Formula (1) may be formed into a film by a vacuum evaporation method, it is suitably formed by the solution coating method using the liquid composition which concerns on this embodiment. Ru.

  Specific examples of the solution coating method include spin coat method, casting method, micro gravure coat method, gravure coat method, bar coat method, roll coat method, and the like. Roll coat method wire bar coat method dip coat method spray coat method screen printing method flexographic printing method offset B) printing method, ink jet printing method and the like.

  The solvent used for the liquid composition is not particularly limited as long as it can dissolve the compound represented by Formula (1).

  Moreover, it does not specifically limit as a film-forming method of layers other than the organic layer containing the compound represented by Formula (1), For example, a vacuum evaporation method, the solution coating method, etc. can be mentioned.

  As the substrate 110, a substrate used in a general organic EL element can be used. For example, a glass substrate, a semiconductor substrate such as a silicon substrate, a transparent plastic substrate, etc. It can be mentioned.

The first electrode 120 is formed on the substrate 110. Specifically, the first electrode 120 is an anode and is made of a metal, an alloy, a conductive compound, or the like, which has a large work function. The first electrode 120 is made of, for example, indium tin oxide (In ₂ O ₃ -SnO ₂ : ITO), indium zinc oxide (In ₂ O ₃ -ZnO), tin oxide (SnO ₂ ), or oxide excellent in transparency and conductivity. A transparent conductive film such as zinc (ZnO) may be formed as a transmission electrode. Further, the first electrode 120 may be formed as a reflective electrode by laminating magnesium (Mg), aluminum (Al) or the like on the transparent conductive film.

  The hole injection layer 130 is formed on the first electrode 120. The hole injection layer 130 is a layer that facilitates the injection of holes from the first electrode 120, and is preferably formed with a thickness of about 10 nm to about 1000 nm, more preferably about 10 nm to about 100 nm. .

  The hole injection layer 130 can be formed using a known hole injection material. As the hole injection material, for example, triphenylamine-containing polyether ketone (poly (ether ketone) -contaminating triphenylamine: TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (4-isopropyl) -4'-methyldiphenylydononium tetrakis (pentafluorophenyl) borate: PPBI), N, N'-diphenyl-N, N'-bis- [4- (phenyl-m-tolyl-amino) -phenyl] -biphenyl-4,4 ' -Diamine (N, N'-diphenyl-N, N'-bis- [4- (phenyl-m-tolyl-amino) -phenyl] -bipheny l-4,4'-diamine: DNTPD), copper phthalocyanine, 4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine (4,4', 4" -tris ( 3-Methylphenylphenylamino) triphenylamine: m-MTDATA), N, N'-di (1-naphthyl) -N, N'-diphenylbenzidine (N, N'-di (1-naphthyl) -N, N'-diphenylbenzidine: NPB), 4,4 ′, 4 ′ ′-tris (diphenylamino) triphenylamine (4,4 ′, 4 ′ ′-tris (diphenylamino) triphenylamine: TDATA), 4,4 ′, 4 ′ ′-tris (N, N) -2-naphthylphenyla )) Triphenylamine (4,4 ', 4 "-tris (N, N -2- naphthylphenylamino) triphenylamine: 2-TNATA), polyaniline / dodecylbenzenesulfonic acid (polyaniline / dodecylbenzenesulfonic acid), poly (3, 4- To include ethylenedioxythiophene) / poly (4-styrenesulfonate) (poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate)), polyaniline / 10-camphorsulfonic acid, etc. Can.

  The hole transport layer 140 is formed on the hole injection layer 130. The hole transport layer 140 is a layer having a function of transporting holes, and is formed, for example, to a thickness of about 10 nm to about 150 nm.

  The hole transport layer 140 can be formed using a known hole transport material. As the hole transport material, for example, 1,1-bis [(di-4-tolylamino) phenyl] cyclohexane (1,1-bis [(di-4-tolylamino) phenyl] cyclohexane: TAPC), N-phenylcarbazole (N-phenylcarbazole), carbazole (carbazole) derivatives such as polyvinylcarbazole (polyvinylcarbazole), N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4 '-Diamine (N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4'-diamine: TPD), 4,4', 4 "-tris (N-carbazolyl) triphenylamine ( , 4 ', 4 "-tris (N-carbazolyl) triphenylamine: TCTA), N, N'- di (1-naphthyl)-N, N'- diphenyl benzidine (N, N'- di (1- napthyl)- N, N'- diphenylbenzidine (NPB) etc. can be mentioned.

  The light emitting layer 150 is formed on the hole transport layer 140. The light emitting layer 150 is a layer that emits light such as fluorescence and phosphorescence, and is formed by a vacuum evaporation method, a spin coating method, an inkjet method, or the like. The light emitting layer 150 is formed, for example, to a thickness of about 10 nm to about 60 nm. As a light emitting material included in the light emitting layer 150, a known light emitting material can be used. However, it is preferable that the light-emitting material contained in the light-emitting layer 150 can emit light from triplet excitons, that is, can emit phosphorescence. In such a case, the device life of the organic EL device 100 can be further improved.

  Moreover, it is preferable that the light emitting layer 150 is formed by the solution apply | coating method using the liquid composition which concerns on this embodiment. Thereby, the light emitting layer 150 containing the compound represented by Formula (1) which can improve the current efficiency and the element life of the organic EL element 100 can be efficiently formed in a large area.

  However, in the case where the other organic layer constituting the organic EL element 100 includes the compound represented by Formula (1) as the charge transport material, the light emitting layer 150 is combined with the compound represented by Formula (1) It may contain a host material that exhibits good performance.

  As a host material, for example, tris (8-quinolinolato) aluminum (tris (8-quinolinato) aluminum: Alq3), 4,4'-bis (carbazol-9-yl) biphenyl (4,4'-bis (carbazol-) 9-yl) biphenyl: CBP), poly (n-vinylcarbazole) (poly (n-vinylcarbazole): PVK), 9, 10-di (naphthalen-2-yl) anthracene (9, 10-di (naphthalene)) anthracene: ADN), 4,4 ′, 4 ′ ′-tris (N-carbazolyl) triphenylamine (4,4 ′, 4 ′ ′-tris (N-carbazolyl) triphenylamine: TCTA), 1,3,5-tris ( N-phenyl benzimi Zol-2-yl) benzene (1,3,5-tris (N-phenyl-benzimidazol-2-yl) benzene: TPBI), 3-tert-butyl-9,10-di (naphth-2-yl) anthracene (3-tert-butyl-9,10-di (naphth-2-yl) anthracene: TBADN), distyrylarylene (DSA), 4,4'-bis (9-carbazole) -2,2'- Dimethyl-biphenyl (4,4'-bis (9-carbazole) 2,2'-dimethyl-bipheny: dmCBP) etc. can be mentioned.

  Here, specific examples of the light emitting material are illustrated below. However, the light emitting material is not limited to the compounds exemplified below.

また、発光層１５０は、ドーパント材料を含んでいてもよい。ドーパント材料としては、例えば、ペリレン（ｐｅｒｌｅｎｅ）及びその誘導体、ルブレン（ｒｕｂｒｅｎｅ）及びその誘導体、クマリン（ｃｏｕｍａｒｉｎ）及びその誘導体、４−ジシアノメチレン−２−（ｐ−ジメチルアミノスチリル）−６−メチル−４Ｈ−ピラン（４−ｄｉｃｙａｎｏｍｅｔｈｙｌｅｎｅ−２−（ｐ−ｄｉｍｅｔｈｙｌａｍｉｎｏｓｔｙｒｙｌ）−６−ｍｅｔｈｙｌ−４Ｈ−ｐｙｒａｎ：ＤＣＭ）及びその誘導体、ビス［２−（４，６−ジフルオロフェニル）ピリジネート］ピコリネートイリジウム（ＩＩＩ）（ｂｉｓ［２−（４，６−ｄｉｆｌｕｏｒｏｐｈｅｎｙｌ）ｐｙｒｉｄｉｎａｔｅ］ｐｉｃｏｌｉｎａｔｅ ｉｒｉｄｉｕｍ（ＩＩＩ）：ＦＩｒｐｉｃ）、ビス（１‐フェニルイソキノリン）（アセチルアセトネート）イリジウム（ＩＩＩ）（ｂｉｓ（１−ｐｈｅｎｙｌｉｓｏｑｕｉｎｏｌｉｎｅ）（ａｃｅｔｙｌａｃｅｔｏｎａｔｅ）ｉｒｉｄｉｕｍ（ＩＩＩ）：Ｉｒ（ｐｉｑ）_２（ａｃａｃ））、トリス（２−フェニルピリジン）イリジウム（ＩＩＩ）（ｔｒｉｓ（２−ｐｈｅｎｙｌｐｙｒｉｄｉｎｅ）ｉｒｉｄｉｕｍ（ＩＩＩ）：Ｉｒ（ｐｐｙ）_３）等のイリジウム（Ｉｒ）錯体、オスミウム（Ｏｓ）錯体、白金錯体等を挙げることができる。

The light emitting layer 150 may also contain a dopant material. As a dopant material, for example, perylene (perlene) and its derivative, rubrene (rubrene) and its derivative, coumarin (coumarin) and its derivative, 4-dicyanomethylene-2- (p-dimethylaminostyryl) -6-methyl- 4H-Pyran (4-dicyanomethylene-2- (p-dimethylaminostyryl) -6-methyl-4H-pyran: DCM) and its derivative, bis [2- (4,6-difluorophenyl) pyridinate] picolinate iridium (III) (Bis [2- (4,6-difluorophenyl) pyridine] picolinate iridium (III): FIrpic), bis (1-phenylisoquinoline) (acetylaceto) Nitrate) iridium (III) (bis (1-phenylisoquinoline) (acetylacetonate) iridium (III): Ir (piq) ₂ (acac), tris (2-phenylpyridine) iridium (III) (tris (2-phenylpyridine)) iridium (III): Iridium (Ir) complexes such as Ir (ppy) ₃ ), osmium (Os) complexes, platinum complexes and the like.

  An electron transport layer 160 is formed on the light emitting layer 150. The electron transport layer 160 is a layer having a function of transporting electrons, and is formed by a vacuum evaporation method, a spin coating method, an inkjet method, or the like. The electron transport layer 160 is formed, for example, to a thickness of about 15 nm to about 50 nm.

  The electron transport layer 160 can be formed using a known electron transport material. Examples of the electron transporting material include tris (8-quinolinolato) aluminum (tris (8-quinolinato) aluminum: Alq3), a compound having a nitrogen-containing aromatic ring, and the like. As a specific example of a compound having a nitrogen-containing aromatic ring, for example, 1,3,5-tri [(3-pyridyl) -phen-3-yl] benzene (1,3,5-tri [(3-pyridine)] A compound containing a pyridine (pyridine) ring such as -phen-3-yl] benzene, 2,4,6-tris (3 '-(pyridin-3-yl) biphenyl-3-yl) -1,3, Compounds containing a triazine (triazine) ring such as 5-triazine (2,4,6-tris (3 '-(pyridin-3-yl) biphenyl-3-yl) -1,3,5-triazine), 2 -(4- (N-phenylbenzoinidazolyl-1-yl-phenyl) -9,10-dinaphthylanthracene (2- (4- (N-phenylbenzoimidazol) l-1-yl-phenyl) -9,10-dinaphthylanthracene) such imidazole (imidazole) can be exemplified compounds comprising a ring.

An electron injection layer 170 is formed on the electron transport layer 160. The electron injection layer 170 is a layer having a function of facilitating the injection of electrons from the second electrode 180, and is formed by a vacuum evaporation method or the like. The electron injection layer 170 is formed, for example, to a thickness of about 0.3 nm to about 9 nm. The electron injection layer 170 can be formed using a known electron injection material. As the electron injecting material, for example, (8-quinolinolato) lithium ((8-quinolinato) lithium: Liq), lithium compounds such as lithium fluoride (LiF), sodium chloride (NaCl), cesium fluoride (CsF) And lithium oxide (Li ₂ O), barium oxide (BaO) and the like.

The second electrode 180 is formed on the electron injection layer 170. Specifically, the second electrode 180 is a cathode, and is made of a metal, an alloy, a conductive compound or the like having a small work function. The second electrode 180 is made of, for example, a metal such as lithium (Li), magnesium (Mg), aluminum (Al), calcium (Ca), aluminum-lithium (Al-Li), magnesium-indium (Mg-In), magnesium -An alloy such as silver (Mg-Ag) may be formed as a reflective electrode. In addition, the second electrode 180 is a transmissive type of a transparent conductive film such as a thin film of 20 nm or less of the above metal, indium tin oxide (In ₂ O ₃ -SnO ₂ ), indium zinc oxide (In ₂ O ₃ -ZnO), etc. It may be formed as an electrode.

  Heretofore, an example of the organic EL element according to the present embodiment has been described. The organic EL device according to the present embodiment can improve the current efficiency and the device life by having the organic layer containing the compound represented by the formula (1).

  The layered structure of the organic EL element according to the present embodiment is not limited to the layered structure of the organic EL element 100. The organic EL element according to the present embodiment may have another known laminated structure. For example, in the organic EL element 100, one or more of the hole injection layer 130, the hole transport layer 140, the electron transport layer 160, and the electron injection layer 170 may be omitted. Moreover, in the organic EL element 100, another layer may be further formed. Furthermore, in the organic EL element 100, each layer may be formed of a plurality of layers.

  For example, in the organic EL element 100, a hole blocking layer is further formed between the hole transporting layer 140 and the light emitting layer 150 in order to prevent the diffusion of excitons or holes into the electron transporting layer 160. May be The hole blocking layer can be formed using, for example, an oxadiazole derivative, a triazole derivative, a phenanthroline derivative, or the like.

  Below, the compound for organic EL elements and organic EL element which concern on this embodiment are concretely demonstrated, referring an Example and a comparative example. In addition, the Example shown below is an example to the last, and the compound for organic EL elements and organic EL element which concern on this embodiment are not limited to the Example shown below.

Synthesis Example 1
(Synthesis of Intermediate 1)
2-Chloro-4-phenyl-6 (5′-phenyl [1,1 ′: 3 ′, 1 ′ ′-terphenyl] -3-yl) -1,3,5 in a reaction vessel under argon. -Triazine (4.00 g, 7.67 mmol), 3-phenyl-5- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) phenyl) -9H-carbazole ( 2.95 g, 7.67 mmol), bis (triphenylphosphine) palladium (II) dichloride (0.11 g, 0.15 mmol), sodium carbonate (2.03 g, 19.18 mmol), dioxane (77 ml), water (38 ml) ) Was added and mixed. Next, the mixture was stirred at 85 ° C. for 4 hours, and after completion of the reaction, the reaction mixture was allowed to cool to room temperature, and impurities were filtered off using Celite (registered trademark). Next, the solvent was distilled off, and the residue was purified by column chromatography and then dispersed and washed with methanol to obtain Intermediate 1 (2.92 g).

＜合成例２＞
（化合物１の合成）
アルゴン下において、反応容器中に、中間体１（２．３０ｇ、２．９５ｍｍｏｌ）、２−ブロモ−９，９'−スピロビ［フルオレン］（１．２８ｇ、３．２５ｍｍｏｌ）、トリス（ジベンジリデンアセトン）ジパラジウム（０）（０．１３５ｇ、０．１５ｍｍｏｌ）、（ｔＢｕ）_３Ｐ／ＢＦ_４（０．０９ｇ、０．３０ｍｍｏｌ）、ナトリウムｔｅｒｔ−ブトキシド（０．８５ｇ、８．８６ｍｍｏｌ）、キシレン（４６ｍｌ）を加えた後、混合した。次に、混合物を１２０℃で６時間撹拌し、反応が終了した後、反応混合液を室温まで放冷し、セライト（Ｃｅｌｉｔｅ：登録商標）を用いて不純物をろ別した。次に、溶媒を留去した後、カラムクロマトグラムにより精製し、化合物１を得た（６ｇ）。

Synthesis Example 2
(Synthesis of Compound 1)
Intermediate 1 (2.30 g, 2.95 mmol), 2-bromo-9,9'-spirobi [fluorene] (1.28 g, 3.25 mmol), tris (dibenzylideneacetone) in a reaction vessel under argon ) Dipalladium (0) (0.135 g, 0.15 mmol), (tBu) ₃ P / BF ₄ (0.09 g, 0.30 mmol), sodium tert-butoxide (0.85 g, 8.86 mmol), xylene ( After adding 46 ml), they were mixed. Then, the mixture was stirred at 120 ° C. for 6 hours, and after completion of the reaction, the reaction mixture was allowed to cool to room temperature, and impurities were filtered off using Celite (registered trademark). Next, the solvent was distilled off, and the residue was then purified by column chromatography to obtain compound 1 (6 g).

＜合成例３＞
（中間体２の合成）
アルゴン下において、反応容器中に、９−（４−ビフェニルイル）−３−ブロモカルバゾール（５．００ｇ、１２．５５ｍｍｏｌ）、３−（４，４，５，５，−テトラメチル−１，３，２−ジキサボロラン−２−イル）カルバゾール（３．３１ｇ、１１．３０ｍｍｏｌ）、ビス（トリフェニルホスフィン）パラジウム（ＩＩ）ジクロライド（０．１８ｇ、０．２５ｍｍｏｌ）、炭酸ナトリウム（３．３３ｇ、３１．３８ｍｍｏｌ）、ジオキサン（１２６ｍｌ）、水（６３ｍｌ）を加えた後、混合した。次に、混合物を８５℃で４時間撹拌し、反応が終了した後、反応混合液を室温まで放冷し、セライト（Ｃｅｌｉｔｅ：登録商標）を用いて不純物をろ別した。次に、溶媒を留去し、カラムクロマトグラムにより精製した後、再沈殿し、中間体２を得た（６．５ｇ）。

Synthesis Example 3
(Synthesis of Intermediate 2)
In a reaction vessel under argon, 9- (4-biphenylyl) -3-bromocarbazole (5.00 g, 12.55 mmol), 3- (4,4,5,5-tetramethyl-1,3. , 2-Dixaborolan-2-yl) carbazole (3.31 g, 11.30 mmol), bis (triphenylphosphine) palladium (II) dichloride (0.18 g, 0.25 mmol), sodium carbonate (3.33 g, 31. After adding 38 mmol), dioxane (126 ml) and water (63 ml), they were mixed. Next, the mixture was stirred at 85 ° C. for 4 hours, and after completion of the reaction, the reaction mixture was allowed to cool to room temperature, and impurities were filtered off using Celite (registered trademark). Next, the solvent was distilled off and the residue was purified by column chromatography and then reprecipitated to obtain Intermediate 2 (6.5 g).

＜合成例２＞
（化合物２の合成）
アルゴン下において、反応容器中に、中間体２（３．００ｇ、６．１９ｍｍｏｌ）、４−ブロモ−９，９'−スピロビフルオレン（２．２０ｇ、５．５７ｍｍｏｌ）、トリス（ジベンジリデンアセトン）ジパラジウム（０）（０．１１３ｇ、０．１２ｍｍｏｌ）、（ｔＢｕ）_３Ｐ／ＢＦ_４（０．１４ｇ、０．５０ｍｍｏｌ）、ナトリウムｔｅｒｔ−ブトキシド（０．８９ｇ、９．２９ｍｍｏｌ）、キシレン（２６ｍｌ）を加えた後、混合した。次に、混合物を１２０℃で６時間撹拌し、反応が終了した後、反応混合液を室温まで放冷し、セライト（Ｃｅｌｉｔｅ：登録商標）を用いて不純物をろ別した。次に、溶媒を留去した後、カラムクロマトグラムにより精製し、化合物２を得た（２ｇ）。

Synthesis Example 2
(Synthesis of Compound 2)
Intermediate 2 (3.00 g, 6.19 mmol), 4-bromo-9,9'-spirobifluorene (2.20 g, 5.57 mmol), tris (dibenzylideneacetone) in a reaction vessel under argon dipalladium _{(0) (0.113g, 0.12mmol)} , (tBu) 3 P / BF 4 (0.14g, 0.50mmol), sodium tert- butoxide (0.89g, 9.29mmol), xylene (26 ml ) Was added and mixed. Then, the mixture was stirred at 120 ° C. for 6 hours, and after completion of the reaction, the reaction mixture was allowed to cool to room temperature, and impurities were filtered off using Celite (registered trademark). Next, the solvent was distilled off, and the residue was then purified by column chromatography to obtain Compound 2 (2 g).

［実施例１〜６、比較例１］
＜有機ＥＬ素子の製造＞
次に、以下の工程によって、有機ＥＬ素子を製造した。

[Examples 1 to 6, Comparative Example 1]
<Manufacturing of organic EL elements>
Next, the organic EL element was manufactured by the following processes.

  First, PEDOT-PSS (manufactured by Sigma-Aldrich) was formed on a glass substrate with ITO on which a 150 nm-thick indium tin oxide (ITO) film in the form of stripes was formed as a first electrode (anode) in advance. ) Was applied by spin coating to form a hole injection layer of 15 nm in thickness.

  Next, P-1 and FA-14 were dissolved in anisole to prepare a coating solution for a hole transport layer. Here, FA-14 was blended so as to be 20% by mass with respect to the total mass of the hole transport layer. The coating solution for a hole transport layer was applied on the above-mentioned hole injection layer by a spin coating method to form a hole transport layer having a thickness of 125 nm. Here, the chemical formulas of P-1 and FA-14 are shown below. In addition, P-1 was synthesize | combined based on the synthesis method described in international publication 2011/159872.

次に、ホスト材料（表１参照）、ドーパント材料としての、トリス（２−（３−ｐ−キシイル）フェニル）ピリジン イリジウム（ＩＩＩ）（ｔｒｉｓ（２−（３−ｐ−ｘｙｌｙｌ）ｐｈｅｎｙｌ）ｐｙｒｉｄｉｎｅ ｉｒｉｄｉｕｍ（ＩＩＩ）（ＴＥＧ））を安息香酸メチルに溶解させ、発光層用塗布液を調製した。ここで、ドーパント材料のドープ量は、発光層の総質量に対して１０質量％とした。次に、上記の正孔輸送層上に、発光層用塗布液をスピンコート法により塗布し、厚さ５５ｎｍの発光層を形成した。

Next, as a host material (see Table 1), tris (2- (3-p-xyl) phenyl) pyridine iridium (III) (tris (2- (3-p-xylyl) phenyl) pyridine iridium as a dopant material (III) (TEG)) was dissolved in methyl benzoate to prepare a coating solution for a light emitting layer. Here, the doping amount of the dopant material is 10% by mass with respect to the total mass of the light emitting layer. Next, on the above-mentioned hole transport layer, a coating solution for a light emitting layer was applied by a spin coating method to form a 55 nm thick light emitting layer.

  Lithium quinolate (Liq) and KLET-03 (manufactured by Chemipro Chemical Industries, Ltd.) are co-deposited on the light emitting layer formed above by vacuum deposition so that the mass ratio is 1: 1, and an electron having a thickness of 20 nm A transport layer was formed.

  Lithium quinolate (Liq) was vapor deposited on the electron transporting layer formed above by a vacuum evaporation method to form an electron injecting layer having a thickness of 3.5 nm.

  On the electron injection layer formed above, aluminum (Al) was vapor-deposited by a vacuum evaporation method to form a second electrode (cathode) with a thickness of 100 nm. Thus, an organic EL element was obtained.

  Here, chemical formulas of Compounds 3 to 7 used as host materials are shown below. Compounds 3 to 5 were synthesized according to the synthesis methods described in WO 2012/087955, WO 2016/033167, and WO 2016/033167, respectively. Compounds 6 and 7 were synthesized according to the synthesis method described in US Patent Application Publication No. 2017-174705.

また、ドーパント材料として用いたＴＥＧの化学式を以下に示す。

The chemical formula of TEG used as a dopant material is shown below.

＜有機ＥＬ素子の電流効率及び素子寿命＞
以下の方法により、実施例３〜８、比較例１の有機ＥＬ素子の電流効率及び素子寿命を評価した。

<Current efficiency and device life of organic EL device>
The current efficiency and the device life of the organic EL devices of Examples 3 to 8 and Comparative Example 1 were evaluated by the following methods.

A predetermined voltage was applied to each organic EL element using a DC constant voltage power source meter (manufactured by KEYENCE) to cause the organic EL element to emit light. At this time, the luminance of the emitting organic EL element was measured using a luminance measurement device SR-3 (manufactured by Topcom). Next, the current was gradually increased, and after measuring the current density at which the luminance became 6000 cd / m ² , the current was made constant and left to stand. The current efficiency was calculated from the obtained current density.

  In addition, the time (LT95) until the luminance value of the light emitting organic EL element gradually decreased and reached 95% of the initial measurement value was measured as the element life.

  Table 1 shows the evaluation results of the current efficiency and the device life of the organic EL device. In Table 1, the ratio of the host material means the mass ratio, and the current efficiency and the device life are relative values when the measured value of the organic EL device of Comparative Example 1 is 100.

表１から、化合物１を単独で用いた実施例１の有機ＥＬ素子は、従来の化合物６と化合物７を組み合わせて用いた比較例１の有機ＥＬ素子よりも、電流効率及び素子寿命が優れ
ていることがわかる。

From Table 1, the organic EL device of Example 1 using Compound 1 alone has superior current efficiency and device life to the organic EL device of Comparative Example 1 using the conventional Compound 6 and Compound 7 in combination. I understand that

  Moreover, it turns out that the lifetime of an element is further improved in the organic EL elements of Examples 2 to 6 in which the compound 1 and the compounds 2 to 5 are used in combination.

<Glass transition temperature of compound and solubility in methyl benzoate>
The glass transition temperature (Tg) of Compounds 1 and 2 (see Examples 1 and 3) and the solubility in methyl benzoate were measured.

  Here, the glass transition temperature (Tg) of the compound was measured using SII DSC6220 (manufactured by Seiko Instruments Inc.) in accordance with JIS K 7121.

  In addition, the solubility of the compound in methyl benzoate is determined by visual observation of the mixture after the compound and methyl benzoate are sufficiently mixed so that the concentration of the compound becomes a predetermined value under an environment of 25 ° C. It was measured. Specifically, when the mixture was transparent, it was determined that the compound was dissolved, and when the mixture was opaque, it was determined that the compound was not dissolved.

  Table 2 shows the evaluation results of the Tg of the compounds 1 and 2 and the solubility in methyl benzoate.

表２から、化合物１、２は、耐熱性と溶解性に優れており、溶液塗布法のための有機ＥＬ素子用材料として適していることがわかる。

From Table 2, it turns out that the compounds 1 and 2 are excellent in heat resistance and solubility, and are suitable as a material for an organic EL element for a solution coating method.

  Although the present embodiment has been described above, the present invention is not limited to the present embodiment. It is apparent that those skilled in the art to which the present invention belongs can conceive of various changes or modifications within the scope of the technical idea described in the claims. The configuration of is also within the technical scope of the present invention.

100 organic EL element 110 substrate 120 first electrode 130 hole injection layer 140 hole transport layer 150 light emitting layer 160 electron transport layer 170 electron injection layer 180 second electrode

Claims (8)

The compound for organic electroluminescent elements represented by following formula (1).

(In the formula (1), A is a group obtained by removing one hydrogen atom from the compound represented by the following formula (2), n is an integer of 2 to 8, and L is an n-valent A linking group, which may be a single bond)

(In formula (2), A _{1 to} A ₄ each independently represent a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group, and A ₁ and A ₂ And X may be bonded to each other to form a ring, and X may be —N = or —CR = (wherein R is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted A plurality of X may be the same or different, and at least one of A ₃ and A ₄ is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group); An aryl group, a substituted or unsubstituted azine ring group, or a heteroaryl group including a group represented by the following formula (3), which contains a non-substituted azine ring group or a group represented by the following formula (3) , _{A 3} and A Position is asymmetric but to be replaced.)

(In the formula (3), X represents -N = or -CR ₁ = (wherein R ₁ represents a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or substituted group And X's may be the same as or different from each other, and Y represents -O-, -S-, -NR _2- (wherein R ₂ is a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group), or -CR 3 R ₄ -. _(wherein, R ₃ and R ₄ each independently represent a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group), and Z is , Substitution or A substituted ring-forming C6-30 aromatic hydrocarbon ring or a substituted or unsubstituted aromatic heterocyclic ring atoms 5 to 30, R ₅ is a substituted or unsubstituted aryl group, a substituted or It is an unsubstituted heteroaryl group or a substituted or unsubstituted alkyl group.)   The compound for an organic electroluminescent device according to claim 1, wherein Z is a six-membered ring in the formula (3).   The compound for organic electroluminescent elements of Claim 1 or 2 whose molecular weight is 850-3000.   The compound for organic electroluminescent elements as described in any one of Claim 1 to 3 whose solubility with respect to methyl benzoate at 25 degreeC is 0.5 mass% or more.   The compound for organic electroluminescent elements as described in any one of Claims 1-4 used as a host material or a charge transport material.   The liquid composition containing the compound for organic electroluminescent elements as described in any one of Claims 1-5, and a solvent.   The thin film containing the compound for organic electroluminescent elements as described in any one of Claims 1-5. A first electrode,
A second electrode provided opposite to the first electrode;
An organic layer provided between the first electrode and the second electrode;
The said organic layer is an organic electroluminescent element containing the compound for organic electroluminescent elements as described in any one of Claims 1-5.

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